Roll shifting system for rolling mills

Abstract

The invention relates to a rolling mill of the 4 Hi Mae West type having cylinders for axially shifting the work rolls for a schedule free rolling operation, work roll balance cylinders are mounted in the Mae West blocks and as a result assume a varying off set axially relation with the work roll bearings, a control for the balance cylinders to compensate for the effect the offset conditions would otherwise have on the forces of the balance cylinders to maintain the forces at a predetermined value.

What I claim is: 
     
       1. A rolling mill having a housing with a window formed therein for receiving at least two rolls together with chock assemblies therefore, which rolls generally define an axial direction, said window including immovable guide blocks for said chock assemblies and means for shifting the rolls in opposite axial directions, the improvement comprising: separating means received in said blocks and operatively associated with said chock assemblies such that said chock assemblies move relative to said separating means in said axial direction, for imposing through said chock assemblies applied forces on the ends of each roll having the tendency to deflect the rolls in the plane of the major component of the rolling force generated by the rolls, whereby shifting at least one roll changes said applied forces; and   control means for controlling said applied forces in response to said shifting of at least one of the rolls, including   first determining means for determining the amount of roll shifting, second determining means operatively associated with said first determining means for determining the amount of said change caused by said separating means, and   means responsive to said second determining means for effecting a change in said applied roll deflection forces to maintain the ultimate effect of said forces at a predetermined value.     
     
     
       2. A rolling mill according to claim 1, wherein said chock assemblies are arranged at the opposite ends of each roll,   said separating means comprise piston cylinder assembly means having cylinders disposed in said guide blocks with a piston operatively associated with each chock assembly in a manner that an off set relation exists with respect to said piston cylinder assembly means and a force receiving point of said chock assemblies,   said control means include means for producing a signal representative of said change in the applied force caused by said off set conditions,   as to each roll, two of said piston cylinders assembly means on opposite ends of the same roll are related to each other so that on said shifting said off set condition increases as to one said piston cylinder assembly means and decreases as to the other of said piston cylinder means, and   said responsive means include means for varying the forces applied by said two cylinders assembly means to maintain the ultimate effect of said forces at said predetermined value.   
     
     
       3. A rolling mill according to claim 2, wherein said piston cylinder assembly means comprise for each chock assembly a set of at least two equal area piston cylinders assembly means arranged on both sides of the axes for their associated roll, means for interconnecting said piston cylinders assembly means of one set with the piston cylinders assembly means of a different roll at the same end of the first roll such that the piston cylinders assembly means having the same off set conditions deliver the same forces to their associated chock assembly.   
     
     
       4. A rolling mill according to claim 3, wherein said piston cylinder assembly means are part of a fluid system means, said fluid system means comprising two separate systems for corresponding piston cylinder assembly means of each cooperative sets of piston cylinder assemblies and being capable of delivering to the piston cylinder assembly means the same pressure range, and   wherein said roll shifting means includes separate means for each roll, and   wherein said first determining means includes separate determining means for each roll, and means for operatively associating said separate determining means with a different one of said fluid system means.   
     
     
       5. A rolling mill according to claim 2, wherein said piston cylinder assembly means comprise a cooperative pair for each chock assembly arranged in spaced relation with respect to the axes of its associated roll, and wherein said control means produces said signal for both ends of said rolls and solves the equations:   F1=F(0.5-s/b)       F2=F(0.5+s/b)       where F1 represents corresponding piston cylinder assembly means at the opposite ends of said rolls and F2 represents corresponding different said piston cylinder assembly means at the opposite ends of said rolls, and where:   F=the total said roll deflection force for one end of said rolls,   b=the distance between said piston cylinder assembly means of a said set, and   s=the amount of said roll shift.   
     
     
       6. A rolling mill according to claim 2, wherein said piston cylinder assembly means for each cooperative pair of opposed chock assemblies are arranged to exert their forces in opposite directions, and wherein said control means produces said signal for both ends of said rolls and solves the equations:   F1=F(0.5-s)       F2=F(0.5+s)       where F1 represents corresponding piston cylinder assembly means at the opposite ends of said rolls and F2 represents corresponding different said piston cylinder assembly means at opposite ends of said rolls, and where:   F=the total said roll deflection force for one end of said rolls, and   s=the amount of said roll shift.   
     
     
       7. A rolling mill according to claim 2, wherein thrust means are so arranged between each chock assembly and said piston cylinder assembly means received in said associated guide block as to be displaceable relative to said associated guide block, said thrust means including guiding means guided by said associated guide blocks for controlling the direction of the displacement of said thrust means with the displacement of the piston cylinder assemblies. 
     
     
       8. A rolling mill according to claim 1, wherein said means for axially shifting said roll includes a piston cylinder assembly means, said control means including means for effecting the desired amount of said shifting of said roll relative to a data position,   said first determining means including position transducer means,   said second determining means including computer means, and   said means for effecting a change in said force applied by said separating means including pressure transducer means.